The present invention relates to coding devices and, in particular, a code wheel for imprinting product code information on containers traveling along a packaging conveyor line.
The present invention finds utility with respect to cartons, packages and like containers which must bear legendary information with respect to the manufacturing process. This is particularly true for the food processing industry and the present invention will be described with specific reference thereto although it will be appreciated that the product coder is widely applicable to situations where the coded information is required for each item being packaged. By coding certain categories of manufacturing and product information on the container, each item becomes a referenced and traceable product. For instance, the code may contain data regarding the date and time of manufacture, the product location thereof, as well as product content information. In the event of problems associated with the product, the code will assist in identifying the underlying causes by enabling cross-reference to the process parameters at the time and location of manufacture. Should a recall of products be required, the consumer or merchant will be able to quickly determine whether their goods are involved by examining the product code imprinted on the container. The more information the code contains, the easier it becomes to obtain accurate referencing of the product and its manufacture.
Generally, the product code is printed on the carton contemporaneously with the final packaging of the product. As the filled carton moves along the packaging conveyor line, a suitable portion of the carton, such as the end flap, passes under a rotating code wheel. The code wheel contains a circumferential series of type having raised characters corresponding to the code. As the flap of the carton passes between the code wheel and a back-up roller, the product code is impressed or debossed on the flap. It is of prime importance that the product code be regularly updated with manufacturing time designations. While in some instances a date may be sufficient, generally it is preferred to update the product code on an hourly basis. For each such update in the product code, the production line must be stopped and the code wheel removed or replaced with a code wheel bearing the current information. During this changeover, the entire production line is stopped thereby halting both upstream processing and downstream packaging operations. As production rates oftentimes exceed 200 units per minute, the changeover can result in significant lost production. Inasmuch as these code wheels must provide uniform debossing and printing location on the flap, the wheels must be mounted for synchronized rotation with the conveyor line. Generally, this is provided by a line driven rotating shaft on which the code wheel is rotatably supported. The code wheel is coupled to the shaft by suitable fasteners, such as set-screws or the like, and indexed thereon by keys or flats. The removal and replacment of the code wheels requires operator access to such fasteners. When the line is stopped however, the fastener may not be accessible thereby requiring momentary starting and stopping of the line until the fastener access is obtained. This increases the changeover time and requires high level operator dexterity. The dexterity and orientation requirements result in substantial time being required for the changeover of such devices. The debossing pressure for the product code is provided by hardened back-up wheel which is spring biased against the outer surface of the code wheel with the carton flap passing therebetween. At the high production speeds, the impacting of the code wheel type against the back-up wheel causes a peening of the type characters. Over a period of time, the type clarity is lost and the type must be replaced. However, the new type also presents problems. If significantly higher than the remaining characters, the new character may penetrate the flap and result in a loss of carton integrity after sealing. At the aforementioned high rates of production, the type must be securely retained against centrifugal force while being removable for product code changes. This is typically been provided by the use of a elastomeric o-ring, which is retained in a circumferential groove and engages a groove on the side face of the type. However, the o-ring is subject to wear, particularly at the location of highest change frequency. Due to excessive wear, the type is prone to ejection from the code wheel with the consequent loss of production time and loss of improperly coded product.